To provide a connection structure of an external facing plate (connection without using a cover) capable of being applied to not only a general roof but also a steep gradient roof and an external wall (perpendicular wall).

A horizontal fitting external facing plate 1 is provided with a face plate part 11, a part 12 to be hooked in which an upper edge of the face plate part is bent, a engaging part 13 in which a lower edge is bent, and a folded back engagement part 14 in which right and left side edges are bent, and a connection member 2 is provided with a flat part 21, an abutting part 22 which is brought into contact with the part 12 to be engaged by folding an upper edge of the flat part, and a part 22 to be engaged with a folded back engagement part 14 of the horizontal fitting external facing plate 1 by bending right and left edges. The thickness of the flat part 21 and the part 22 to be engaged in the connection member 2 is approximately equal to or less than the gap between the back side of the face plate part 11 of the upper stage horizontal fitting external facing plate 1 and the upper end of the part 12 to be engaged of the lower stage horizontal external facing plate 1, the side edges of the horizontal fitting external facing plate 1 are opposite to each other with equal interval and fixed, and the connection member 2 is inserted from an upper side of the back side of the opposite part.